RDF between two types of molecules in a box

Hello Everyone,

First thanks for your attention on this question.

I built a mixture in Amorphous cell, with 50 A molecules (CxHyOz) and 50 B molecules (CxHyNz).

My question is, if I would like to calculate RDF between A and B, what should I do?

My current method is to select all A molecules as Set 1, and select all B molecules as Set 2, then using Forcite-RDF module. Is it correct, and this RDF is atoms-atoms RDF or centroid-centroid RDF?  do I have to creat a centroid any more?

By the way, If I want to study A-A interaction/structure, when I choose set 1 and set 1 in Sets, do I have to check "Include intra-intermolecular components"? 

Thanks in advance,
best,
Guangji